Paragangliome der Kopf-Hals-Region („Glomustumoren”)

Pulsatile Tinnitus: Differential Diagnosis and Radiological Work-Up

PURPOSE OF REVIEW

Identification of the underlying cause of pulsatile tinnitus is important for treatment decision making and for prognosis estimation. For this, an adequate diagnostic imaging strategy is crucial.

RECENT FINDINGS

Both CT and MRI can be useful, and in general, these modalities provide complementary diagnostic information. The scanning protocol can be optimized based on the estimated a priori chance for finding specific pathology, or the need to rule out more rare but clinical significant disease. In recent years, dynamic CTA, also referred to as 4D-CTA, has become available as a new technique that enables non-invasive evaluation of hemodynamics for the detection, classification, and follow-up of vascular malformations.

SUMMARY

The value of different diagnostic imaging modalities in the work-up of pulsatile tinnitus is discussed in relation to the differential diagnosis. Furthermore, imaging findings of different diseases are presented, both for CT and MRI.

Paragangliomas of the Head and Neck

Paragangliomas of the head and neck are rare vascular skull-base tumors derived from the paraganglionic system with an estimated incidence of 1:30,000 accounting for 3% of all paragangliomas. The most common paraganglioma locations of the head and neck in descending order are the carotid body, jugular, tympanic, and vagal paragangliomas. This article discusses the clinical characterics, normal anatamy, imaging findings and protocols, pathology, staging, and differential diagnosis for paragangliomas of the head and neck.

Pulsatile tinnitus: imaging and differential diagnosis

BACKGROUND

Pulsatile tinnitus, unlike idiopathic tinnitus, usually has a specific, identifiable cause. Nonetheless, uncertainty often arises in clinical practice about the findings to be sought and the strategy for work-up.

METHODS

Selective literature review and evaluation of our own series of patients.

RESULTS

Pulsatile tinnitus can have many causes. No prospective studies on this subject are available to date. Pulsatile tinnitus requires both a functional organ of hearing and a genuine, physical source of sound, which can, under certain conditions, even be objectified by an examiner. Pulsatile tinnitus can be classified by its site of generation as arterial, arteriovenous, or venous. Typical arterial causes are arteriosclerosis, dissection, and fibromuscular dysplasia. Common causes at the arteriovenous junction include arteriovenous fistulae and highly vascularized skull base tumors. Common venous causes are intracranial hypertension and, as predisposing factors, anomalies and normal variants of the basal veins and sinuses. In our own series of patients, pulsatile tinnitus was most often due to highly vascularized tumors of the temporal bone (16%), followed by venous normal variants and anomalies (14%) and vascular stenoses (9%). Dural arteriovenous fistulae, inflammatory hyperemia, and intracranial hypertension were tied for fourth place (8% each).

CONCLUSION

The clinical findings and imaging studies must always be evaluated together. Thorough history-taking and clinical examination are the basis for the efficient use of imaging studies to reveal the cause of pulsatile tinnitus.